1. Field of the Invention
The present invention relates to an apparatus for mixing a play video signal generated by playing a recording medium with a graphics video signal generated on the basis of data processing.
2. Description of the Related Background Art
In video equipment such as a video game machine employing graphics video images, for example as disclosed in Japanese Patent Application Kokai No. 64-78319, data such as character data stored in V-RAM is read in accordance with a program, image data is generated on dot-by-dot basis, in accordance with the read data, and the image data is supplied to an encoder to be converted to RGB data indicative of a corresponding color tone in a color table. Further, the RGB data is converted to an analog RGB signal from which a composite video signal is created and used as a graphics video signal.
In such video equipment, it is thought to mix a graphics video signal generated as described above with a play video signal representative of a moving image or a still image produced by playing a recording medium such as a video disc in order to create various video images. In this case, determination is made as to the kind of an image produced by image data, for example, whether the data represents a character portion such as a person or data for producing a background portion, and one of the play video signal and the graphics video signal is selectively issued in accordance with the determination result.
However, after the image data is produced, a time necessary for the encoder to generate a graphics video signal for the image data is different from a time necessary to select a kind of image, thereby failing to superimpose a graphics video image produced by the graphics video signal with a play video image produced by the play video signal at a desired position on the screen. For example, when a play video image P is to be inserted in a circular form in a graphics video image G, as shown in FIG. 1, the play video image P may be actually inserted at a position indicated by a solid line which is different from a desired position indicated by a broken line, whereby a hatched portion, which should be hidden by the play video image, may appear as a graphic video image, and the video image P is displayed at a displaced position, thus presenting an undesired video image.